NAME
XML::XSS - XML stylesheet system
VERSION
version 0.3.3
SYNOPSIS
use XML::XSS;
my $xss = XML::XSS->new;
$xss->set( pod => {
pre => "=pod\n",
post => "=cut\n",
} );
$xss->set( section => {
pre => \&pre_section
} );
sub pre_section {
my ( $self, $node, $args ) = @_;
return "=head1 " . $node->findvalue( '@title' ) . "\n\n";
}
print $xss->render( <
XML::XSS - a XML stylesheet system
...
END_XML
DESCRIPTION
Caution: this is alpha-quality software. Here be enough dragons to send
Beowulf packing. Caveat maximus emptor.
"XML::XSS" is a XML stylesheet system loosely similar to CSS and XSLT. A
"XML::XSS" object is made up of rendering rules that dictate how the
different nodes of an XML document are to be rendered, and can be
applied against one or many XML documents.
"XML::XSS" is a rewrite of XML::XPathScript, which was initially part of
the AxKit framework.
The XML Document
"XML::XSS" uses XML::LibXML under the hood as its XML DOM API. Documents
can be passed as strings, in which case the creation of the XML::LibXML
object will be done behind the curtain
$xss->render( 'yadah' );
or the XML::LibXML object can be passed directly
my $doc = XML::LibXML->load_xml( location => 'foo.xml' );
$xss->render( $doc );
Stylesheet Rules
"XML::XSS" has 5 different kinds of rules that reflect the different
kinds of nodes that a XML document can have (as per XML::LibXML):
XML::XSS::Document, XML::XSS::Text, XML::XSS::Comment,
XML::XSS::ProcessingInstruction and XML::XSS::Element. Whereas there are
can many "XML::LibXML::Element" rules, there is only one instance of
each of the first 4 rules per stylesheet. In addition of the regular
"XML::LibXML::Element" rules, a special *catch-all*
"XML::LibXML::Element" also exists that will be applied to any document
element not explicitly matched by one of the element rules.
Rules Style Attributes
Each rule has a set of style attributes that control how the matching
document node is transformed. The different types of rule
(XML::XSS::Document, XML::XSS::Element, XML::XSS::Text,
XML::XSS::Comment and XML::XSS::ProcessingInstruction) have each a
different set of style attributes, which are described in their relative
manpages.
Unless specified otherwise, a style attribute can be assigned a scalar
value or a reference to a sub. In the second case, the sub will be
evaluated in the context of the processed node and its return value will
be used as the style attribute value.
Upon execution, the sub references will be passed three parameters: the
invoking rule, the "XML::LibXML" node it is rendering and the arguments
ref given to "render()".
$css->set( 'foo' => {
pre => '[[[',
post => sub {
my ( $self, $node, $args ) = @_;
return $node->findvalue( '@bar' );
}
} );
Modifying Rules While Rendering
Rules attributes changed while rendering only apply to the current
element.
$xss->set( 'section' => {
process => sub {
my ( $self, $node ) = @_;
$self->stash->{section_nbr}++;
if ( $self->stash->{section_nbr} == 5 ) {
# only applies to the one section
$self->set_pre( '>>> this is the fifth section <<set( 'section' => {
process => sub {
my ( $self, $node ) = @_;
$self->stash->{section_nbr}++;
if ( $self->stash->{section_nbr} == 6 ) {
$self->stylesheet->element('section')->set_pre(
'>>> this is after the fifth section <<text->set( ... );
clear_text()
Shortcut for
$xss->text->clear;
comment
The comment rule.
comment()
Attribute getter.
set_comment( ... )
Shortcut for
$xss->comment->set( ... )
elements
The collection of user-defined element rules.
element( $name )
Returns the XML::XSS::Element node associated to the tag $name. If the
element didn't already exist, it is automatically created.
my $elt = $xss->element( 'foo' ); # element for
$elt->set( pre => '[foo]' );
catchall_element
The catch-all element rule, which is applied to all the element nodes
that aren't explicitly matched.
# change all tags to except for
$xss->set( 'foo' => { showtag => 1 } );
$xss->set( '*' => { rename => 'unknown' } );
catchall_element()
The attribute getter.
stash
The stylesheet has a stash (an hashref) that is accessible to all the
rules during the rendering of a document, and can be used to pass
information back and forth.
$xss->set( section => {
intro => \&section_title,
} );
# turns ...
# into 1. blah
sub section_title {
my ( $self, $node, $args ) = @_;
my $section_nbr = $self->stash->{section_nbr}++;
return $section_nbr . ". " . $node->findvalue( '@title' );
}
By default, the stash is cleared when rendering a document. To change
this behavior, see "use_clean_stash" in XML::XSS::Document.
stash()
The attribute getter.
clear_stash()
Clear the stash.
OVERLOADING
Concatenation (.)
The concatenation operator is overloaded to behave as an alias for
"get()".
my $chapter = $xss.'chapter'; # just like $xss->get('chapter')
$chapter->set_pre( '

' );
$chapter->set_post( '

' );
Gets really powerful when used in concert with the overloading of the
rules and style attributes:
# equivalent as example above
$xss.'chapter'.'pre' *= '

';
$xss.'chapter'.'post' *= '

';
METHODS
set( $element_1 => \%attrs, $element_2 => \%attrs_2, ... )
Sets attributes for a rendering node.
The $name can be an XML element name, or one of the special keywords
"#document", "#text", "#comment", "#pi" or "*" (for the *catch-all*
element), which will resolve to the corresponding rendering object.
$xss->set( 'foo' => { rename => 'bar' } );
# same as $xss->element('foo')->set( rename => 'bar' );
$xss->set( '#text' => { filter => { uc shift } } );
# same as $xss->text->set( filter => { uc shift } );
Note that subsequent calls to "set()" are additive. I.e.:
$xss->set( foo => { pre => 'X' } );
$xss->set( foo => { post => 'Y' } ); # pre is still set to 'X'
If you want to delete an attribute, passes it "undef" as its value.
render( $xml, \%args )
Returns the output produced by the application of the stylesheet to the
xml document. The xml can be passed as a string, or as a "XML::LibXML"
object. Several "XML::LibXML" objects can also be passed, in which case
the return value will be the concatenation of their transformations.
my $sections = $xss->render( $doc->findnodes( 'section' ) );
The %args is optional, and will defaults to an empty hash if not
provided. The reference to %args is also passed to the recursive calls
to "render()" for the children of the processed node, which allows for
another way for parent/children nodes to pass information in addition to
the "stash".
# count the descendents of all nodes
$xss->set(
'*' => {
process => sub {
my ( $self, $node, $attrs ) = @_;
$attrs->{children}++;
return 1;
},
content => sub {
my ( $self, $node, $attrs ) = @_;
my %c_attrs;
my $c_ref = \%c_attrs;
my $output = $self->render( $node->childNodes, $c_ref );
$attrs->{children} += $c_ref->{children};
$self->{post} =
"\n>>> node has "
. ($c_ref->{children}||0)
. " descendents\n";
return $output;
},
} );
AUTHOR
Yanick Champoux
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by Yanick Champoux.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.